US6515577B1 - Channel monitoring by a multichannel selective call receiver - Google Patents
Channel monitoring by a multichannel selective call receiver Download PDFInfo
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- US6515577B1 US6515577B1 US09/341,029 US34102999A US6515577B1 US 6515577 B1 US6515577 B1 US 6515577B1 US 34102999 A US34102999 A US 34102999A US 6515577 B1 US6515577 B1 US 6515577B1
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- Prior art keywords
- channel
- selective call
- information
- receiver
- mandatory frame
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/02—Terminal devices
- H04W88/022—Selective call receivers
Definitions
- This invention relates to selective call receivers, such as pagers, operating in a communication environment.
- this invention relates to, but is not necessarily limited by, channel monitoring by a multichannel selective call receiver operating in a communication environment.
- Selective call receivers such as pagers, of a selective call system receive information transmitted on carrier frequencies or channels within a communication environment. Such information is typically formatted according to messaging protocols defined for the selective call system. For example, Motorola's FLEXTM selective call system has a messaging protocol in which information is grouped into frames which are then A transmitted as a cycle. A FLEXTM cycle has one hundred and twenty eight frames of which some are mandatory frames transmitted at the start of the FLEXTM cycle. Each of the mandatory frames is divided into information fields. Information fields at the start of a mandatory frame can point to more information for a selective call receiver in the rest of the mandatory frame. For example, the address field can address one or more selective call receivers which will have more information provided by the rest of the mandatory frame.
- Receiving information from a FLEXTM cycle requires a selective call receiver to synchronize to the FLEXTM cycle to monitor for the information. Synchronizing has to be attained at or before the mandatory frames to receive information from the information fields of such frames. Upon processing the mandatory frames, other information, such as assigned frames that provide information specifically for the selective call receiver, can be determined to receive more information from the FLEXTM cycle.
- FLEXTM cycles are synchronously transmitted on different channels by referencing such cycles to external time signals provided by, for example, a Global Positioning System. These multichannel selective call receivers are supported by what is referred to as a FLEXTM roaming system. Channels for multichannel selective call receivers in the FLEXTM roaming system are also known as roaming channels.
- Determining which channel to monitor is critical for multichannel selective call receivers in a FLEXTM roaming system as information can be received from different FLEXTM cycles transmitted concurrently on different roaming channels. Each of these different roaming channels should be monitored quickly as there can be a problem of not detecting information transmitted on another. Furthermore, invalid channels which are not roaming channels of the FLEXTM roaming system can provide FLEXTM cycles that may be inadvertently detected. Such invalid channels should be quickly distinguished from valid channels that can provide information to the multichannel selective call receivers.
- a multichannel selective call receiver comprising:
- a receiver for receiving information on a channel, said information being formatted as a cycle having a plurality of frames including at least one mandatory frame having an address field;
- processing means coupled to said receiver,
- processing means is adapted to control said receiver to receive information on other channels within said mandatory frame when said address field does not address said multichannel selective call receiver in said mandatory frame.
- said processing means can be further adapted to control said receiver to receive information on said other channels following said address field and within said mandatory frame.
- said processing means can comprise a controller coupled to a baud detector, said controller being adapted to control said baud detector to perform baud detection of information.
- said processing means can further comprise a timer for determining lapse of a predetermined time period, said timer being associated with said baud detector.
- said processing means can comprise a memory for storing a channel list indicative of channel priority of said channel and said other channels.
- a method for channel monitoring by a multichannel selective call receiver comprising the steps of:
- said step of controlling can comprise the step of determining whether remaining duration of said mandatory frame is sufficient for a baud detection.
- said step of controlling can further comprise the step of selecting a next channel for said baud detection when remaining duration of said mandatory frame is sufficient, said next channel being of a higher or equal priority as indicated within a channel list stored in a memory.
- said step of controlling can further comprise the step of marking said next channel for a synchronization field sample when said baud detection determines that said next channel may be a valid channel.
- said step of controlling can further comprise the step of sampling a synchronization field of a next available mandatory frame of said next channel.
- FIG. 1 shows structure of a mandatory frame in a FLEXTM cycle in accordance with a preferred embodiment of the invention.
- FIG. 2 shows a block diagram of a multichannel selective call receiver for receiving the FLEXTM cycle of FIG. 1;
- FIGS. 3 a and 3 b are flow diagrams showing a method for operating the multichannel selective call receiver of FIG. 2 .
- FIG. 1 shows structure of a mandatory frame 2 in a FLEXTM cycle 1 in accordance with a preferred embodiment of the invention.
- FLEXTM cycle 1 has at least one mandatory frame.
- Mandatory frame 2 has a synchronization field 3 , a block information field 4 , an address field 5 , a vector field 6 and a message field 7 .
- Synchronization field 3 has a bit in a frame information word for indicating that FLEXTM cycle 1 is transmitted on a channel which supports multichannel selective call receivers as defined by the messaging protocol of FLEXTM.
- channels which support multichannel selective call receivers are also referred to as roaming channels.
- a valid channel is a roaming channel that can provide information with FLEXTM cycle 1 to multichannel selective call receivers.
- FIG. 2 shows a block diagram of a multichannel selective call receiver 10 for receiving FLEXTM cycle 1 of FIG. 1 in a FLEXTM roaming system.
- Multichannel selective call receiver 10 comprises a receiver 11 and processing means 12 .
- Receiver 11 couples to an antenna 13 for receiving information on different channels within a FLEXTM communication environment of the FLEXTM roaming system.
- FIG. 2 shows two channels 14 , 15 as examples of the different channels.
- Processing means 12 comprises a controller 16 , a baud detector 17 and a memory 18 .
- Memory 18 stores a channel list indicative of channel priority of the different channels.
- Controller 16 couples to control receiver 11 and baud detector 17 to monitor the different channels.
- processing means 12 When multichannel selective call receiver 10 is receiving at the start of a mandatory frame of a FLEXTM cycle on a channel, processing means 12 is adapted to control receiver 11 to receive information on other channels during the mandatory frame when an address field of the mandatory frame does not address multichannel selective call receiver 10 in the mandatory frame.
- This is possible because the different channels are roaming channels which support multichannel selective call receiver 10 in the FLEXTM roaming system and FLEXTM cycles on such roaming channels are synchronously transmitted. Therefore, multichannel selective call receiver 10 needs only to synchronize to any FLEXTM cycle on any roaming channel in the FLEXTM roaming system to be in synchronization with FLEXTM cycles on other roaming channels.
- the invention advantageously uses information that has to be transmitted for each of the FLEXTM cycles in accordance with the messaging protocol of FLEXTM. This provides a more reliable baud detection to be performed as such information will be present in the mandatory frames for processing by processing means 12 of the invention.
- multichannel selective call receiver 10 in the invention monitors other channels only when a channel that is currently monitored has no information within its mandatory frames to provide to multichannel selective call receiver 10 . The invention, therefore, does not affect multichannel selective call receiver 10 in receiving information on such a channel.
- FIGS. 3 a and 3 b are flow diagrams showing a method 20 for operating multichannel selective call receiver 10 .
- method 20 proceeds to initialising baud detector 17 and a channel selector for selecting a channel from a channel list on which receiver 11 is to receive information.
- the channel list is stored in memory 18 and is indicative of channel priority of the channel and other channels in the channel list.
- controller 16 determines whether receiver 11 is receiving information at the start of a mandatory frame of the channel selected at step 22 . If decision step 23 is a “Yes”, controller 16 checks at decision step 24 whether the mandatory frame is assigned for the channel. If decision step 24 is a “Yes” to indicate that the channel is a valid channel, method 20 then proceeds to step 27 in which controller 16 decodes the mandatory frame for more information. If decision step 24 is a “No”, method then proceeds to decision step 25 in which controller 16 determines whether any channel is marked for “sync field sample” (synchronization field sample).
- a channel is marked for “sync field sample” when a baud detection performed on information from the channel indicates that such a channel may be a valid channel.
- synchronization field 3 of a mandatory frame on the channel will have to be sampled to detect the bit in the frame information word indicating that the channel is a roaming channel.
- method 20 begins from step 21 , only one channel has been selected by the channel selector and is being monitored so that decision step 25 typically has a “No” outcome. However, for a “Yes” outcome from decision step 25 , method 20 will proceed to sampling the channel marked for “sync field sample”. Sampling a channel is according to channel priority as indicated in the channel list stored in memory 18 . Channel priority helps in determining an order in which channels are sampled when more than one channel is marked for “sync field sample”. Upon sampling a channel, a flag for marking the channel for “sync field sample” is reset to indicate that this channel has been sampled.
- method 20 proceeds to decision step 26 in which controller 16 determines whether there is any channel of higher or equal priority to the channel currently selected. If decision step 26 is a “Yes”, method 20 proceeds to performing a “sync field sample” on the highest priority channel at step 29 . If decision step 26 is a “No”, method 20 returns to decision step 23 . Following a “No” from decision step 26 , the channel that has been selected by the channel selector will continue to be processed by processing means 12 for another mandatory frame from decision step 23 as described above.
- Baud detector 17 is associated with a timer that is set to expire after lapse of a predetermined time period. This predetermined time period is variable depending upon, for example, how many different channels that multichannel selective call receiver 10 has to monitor and, consequently, how many FLEXTM cycles are necessary so that baud detection can be performed on information on the different channels. Such a timer can be provided by, for example, timing circuitry within controller 16 .
- Initialising of baud detector 17 at step 22 also includes initialising the timer.
- Method 20 returns to decision step 23 with a “No” from decision step 30 .
- method 20 proceeds to decision step 31 in which controller 16 determines whether remaining duration of a period of the mandatory frame is sufficient for baud detection of information in the mandatory frame on one or more other channels.
- decision step 31 determines whether remaining duration of a period of the mandatory frame is sufficient for baud detection of information in the mandatory frame on one or more other channels.
- decision step 32 determines priority of a next channel in the channel list is determined.
- controller 16 then controls baud detector 17 in performing a baud detection on the next channel in step 33 .
- Decision step 34 determines whether this next channel passes the baud detection. A “Yes” from decision step 34 indicates that this next channel may potentially have information for multichannel selective call receiver 10 . Such a channel is, therefore, marked for a “sync field sample” to be performed at one of its mandatory frame. Marking a channel is by, for example, setting a flag to indicate that a “sync field sample” is required for the channel.
- method 20 checks at decision step 36 whether channels of higher or equal priority in the channel list has been sampled with a baud detection. With a “No” from decision step 36 , controller 16 then selects a next channel from the channel list at step 37 and returns method 20 to decision step 31 . With a “Yes” from decision step 36 , controller 16 then determines in decision step 38 whether any channel has been sampled and marked for a “sync field sample”. A “Yes” from decision step 38 brings method 20 back to decision step 23 . Otherwise, a “No” from decision step 38 brings method 20 back to step 22 .
- the invention advantageously provides for multichannel selective call receiver 10 to sample different channels for information using other information provided by mandatory frames which is always present on such channels. Also, by performing a baud detection prior to a synchronization field sample, only channels that may be valid channels will be processed subsequently. This saves time as invalid channels will not be inadvertently detected and unnecessarily monitored. Furthermore, the invention advantageously allows prioritization of different channels so that a synchronization field at the start of a mandatory frame is more efficiently used and, therefore, channel monitoring is more effective.
Abstract
Description
Claims (13)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SG1997000047A SG71691A1 (en) | 1997-01-10 | 1997-01-10 | Channel monitoring by a multichannel selective call receiver |
SG9700047 | 1997-01-10 | ||
PCT/SG1997/000073 WO1998031166A1 (en) | 1997-01-10 | 1997-12-17 | Channel monitoring by a multichannel selective call receiver |
Publications (1)
Publication Number | Publication Date |
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US6515577B1 true US6515577B1 (en) | 2003-02-04 |
Family
ID=20429569
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/341,029 Expired - Lifetime US6515577B1 (en) | 1997-01-10 | 1997-01-10 | Channel monitoring by a multichannel selective call receiver |
Country Status (6)
Country | Link |
---|---|
US (1) | US6515577B1 (en) |
CN (1) | CN1117494C (en) |
AU (1) | AU5893998A (en) |
HK (1) | HK1024811A1 (en) |
SG (1) | SG71691A1 (en) |
WO (1) | WO1998031166A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020054652A1 (en) * | 2000-04-15 | 2002-05-09 | Kim Hyun Wook | Pager having simultaneous multichannel scanning function and data transmitting/receiving method thereof |
US20040104808A1 (en) * | 2000-08-14 | 2004-06-03 | Housh Khoshbin | Method and system for displaying priority messages on a wireless device |
US20100085951A1 (en) * | 2007-02-09 | 2010-04-08 | Nokia Corporation | Managing unscheduled wireless communication in a multiradio device |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SG77160A1 (en) * | 1998-02-13 | 2000-12-19 | Motorola Inc | Multichannel selective call receiver |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4914649A (en) * | 1988-09-12 | 1990-04-03 | Motorola, Inc. | Multiple frequency message system |
US5555183A (en) | 1991-12-02 | 1996-09-10 | Motorola, Inc | Method and apparatus for synchronizing to a synchronous selective call signal |
US5610919A (en) * | 1995-01-24 | 1997-03-11 | Motorola, Inc. | Network identification information placement architecture for messaging system having roaming capability |
US5634914A (en) | 1987-07-30 | 1997-06-03 | Courtaulds Plc | Cellulosic fibre |
US5682147A (en) * | 1995-01-24 | 1997-10-28 | Motorola, Inc. | Method and apparatus for selecting a receive frequency in a communication receiver |
US5724389A (en) * | 1995-12-08 | 1998-03-03 | Motorola, Inc. | Method and apparatus for detecting a presence of a predetermined baud rate |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4860004A (en) * | 1988-01-04 | 1989-08-22 | Motorola, Inc. | Digital selective calling receiver having a selectively attachable device for multiple independent address decoding capability |
US5635914A (en) * | 1992-05-29 | 1997-06-03 | Motorola, Inc. | Method and apparatus for dynamic group calling in a selective call system |
-
1997
- 1997-01-10 US US09/341,029 patent/US6515577B1/en not_active Expired - Lifetime
- 1997-01-10 SG SG1997000047A patent/SG71691A1/en unknown
- 1997-12-17 CN CN97181337A patent/CN1117494C/en not_active Expired - Fee Related
- 1997-12-17 WO PCT/SG1997/000073 patent/WO1998031166A1/en active IP Right Grant
- 1997-12-17 AU AU58939/98A patent/AU5893998A/en not_active Abandoned
-
2000
- 2000-06-20 HK HK00103694A patent/HK1024811A1/en not_active IP Right Cessation
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5634914A (en) | 1987-07-30 | 1997-06-03 | Courtaulds Plc | Cellulosic fibre |
US4914649A (en) * | 1988-09-12 | 1990-04-03 | Motorola, Inc. | Multiple frequency message system |
US5555183A (en) | 1991-12-02 | 1996-09-10 | Motorola, Inc | Method and apparatus for synchronizing to a synchronous selective call signal |
US5610919A (en) * | 1995-01-24 | 1997-03-11 | Motorola, Inc. | Network identification information placement architecture for messaging system having roaming capability |
US5682147A (en) * | 1995-01-24 | 1997-10-28 | Motorola, Inc. | Method and apparatus for selecting a receive frequency in a communication receiver |
US5724389A (en) * | 1995-12-08 | 1998-03-03 | Motorola, Inc. | Method and apparatus for detecting a presence of a predetermined baud rate |
Non-Patent Citations (1)
Title |
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PCT Int'l Publication No.: WO 89/06475, Int'l Publication Date Jul. 13, 1989, Int'l Patent. |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020054652A1 (en) * | 2000-04-15 | 2002-05-09 | Kim Hyun Wook | Pager having simultaneous multichannel scanning function and data transmitting/receiving method thereof |
US6801121B2 (en) * | 2000-04-15 | 2004-10-05 | Sk Telecom Co., Ltd. | Pager having simultaneous multichannel scanning function and data transmitting/receiving method thereof |
US20040104808A1 (en) * | 2000-08-14 | 2004-06-03 | Housh Khoshbin | Method and system for displaying priority messages on a wireless device |
US20100085951A1 (en) * | 2007-02-09 | 2010-04-08 | Nokia Corporation | Managing unscheduled wireless communication in a multiradio device |
US8374618B2 (en) * | 2007-02-09 | 2013-02-12 | Nokia Corporation | Managing unscheduled wireless communication in a multiradio device |
Also Published As
Publication number | Publication date |
---|---|
CN1244993A (en) | 2000-02-16 |
AU5893998A (en) | 1998-08-03 |
SG71691A1 (en) | 2000-04-18 |
WO1998031166A1 (en) | 1998-07-16 |
HK1024811A1 (en) | 2000-10-20 |
CN1117494C (en) | 2003-08-06 |
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